1. Technical Field
The present invention relates to an ink set and a recording method.
2. Related Art
A recording method using an ink jet recording system is performed by discharging droplets of an ink and allowing the ink droplets to fly and adhere to (land on) a recording medium such as paper. Because of recent innovative progress in the ink jet recording technology, the recording method using the ink jet recording system has been also employed in the field of highly fine image recording (image printing), which was ever achieved by photograph or offset printing.
In order to perform recording with higher fineness by the ink jet recording system, the volume of ink droplets to be discharged must be significantly small, such as several picoliters, and the diameter and the spacing of nozzles for discharging an ink are further reduced. For example, JP-A-2009-287003 discloses an ink jet recording ink containing a specific alkanediol, such as 1,2-hexanediol, that can be applied to a recording head corresponding to high image quality (a recording head composed of first nozzles having a relatively short passage and second nozzles having a relatively long passage alternately arranged at intervals of less than 30 μm).
Unfortunately, since the ink jet recording ink described in JP-A-2009-287003 contains a penetrant having a low boiling point, the volatile organic compounds (VOC) in the organic solvent from a recorded image disadvantageously increase. Accordingly, a reduction in the volume of VOC by using a penetrant having a high normal boiling point may be effective. However, in an ink jet recording ink containing a penetrant having a high normal boiling point, after landing of the ink droplets on a recording medium, water preferentially evaporates to give a penetrant rich state, and the dispersibility of a pigment is destroyed to cause aggregation. Consequently, the graininess of the recorded image is deteriorated. The present inventors have revealed through their studies that this problem significantly occurs in recording on a recording medium having low affinity to ink compositions or in using a thin ink composition having a low pigment concentration.